Joseph k thomas



N0. 6l3,|77. Patented Oct. 25, I898.

- J. N. THOMAS.

SAFETY DEVICE FOR SUSPENDED CDNDUCTORS.

(Application filed Jan. 20, 1898.)

A OHNEY,

UNITED STATES PATENT OFFICE.

JOSEPH N. THOMAS, OF J OHNSTOWN,-PENNSYLVANIA, ASSIGNOR TO THE STEELMOTOR COMPANY, OF SAME PLACE.

SAFETY DEVICE FOR SUSPENDED CONDUCTORS.

SPECIFICATION forming part of Letters Patent No. 613,177, dated October25, 1898.

Application filed January 20, 1898. Serial No. 667,271. (No model.)

To all whom it may concern.-

Be it known that I, JOSEPH N. THOMAS, of J ohnstown, in the county ofCambria and State of Pennsylvania, have invented a new and useful SafetyDevice for Suspended Conductors, of which the followingis a full, clear,and exact description, reference being had to the accompanying drawing,which forms a part of this specification.

My invention is designed to prevent accidents from the breaking andsubsequent falling of suspended electrical conductors. It is especiallyapplicable for use on what are known as overhead electric railways. Inthis class-of railways there is a main source of current-supply, oneside of which is usually in connection with the track-rails, while theother side is connected to insulated feed-wires which convey currentfrom the power-house along the line of way. The overhead naked conductoris arranged in sections of considerable length, each section beinginsulated at its end from the neighboring section. At intervals thesections are connected to one or the other of the main feed-wires. Thedifference of potential in electric railways is ordinarily about fivehundred volts, so that if the conductor, which must of necessity bebared, breaks and falls upon man or beast a very decided shock is giventhem, which may be even suflicient in some cases to cause death.

The object of my invention is to provide simple means for automaticallyopening the circuit between the main feed-wires and a section of thebared conductor, said automatic means being put into operation by theformation of an open circuit in the conductor due to the breakagethereof. To this end I place between the main feed-wire and theconductor-section an electromagnetic switch. The energizing-coil of thisswitch receives a shunt-current, which passes through the entire lengthof the conductor-section and magnetizes the core of the magnet, so as toattract the switch armature and maintain a closed circuit. With thisarrangement an open circuit in the conductor-section will prevent theflow of current through the energizing coil, and the switch willautomatically open.

The drawing is an electrical diagram and shows two modified forms of myinvention.

I have represented the source of electric supply as A, the mainfeed-wire as F, the rail or return side of the circuit as R, and thevarious conductor-sections as T. It is of course clear that instead ofthe single feed-wire shown there may be any desired number, and eachconductor-section T may be connected to a different feed-wire, if it isdeemed desirable.

The electromagnetic switches are represented as B. Each of these iscomposed of a core B coil B vivoted armature l3 and fixed stop S. Theswitch is connected to F by connection O and to T either by connection 0or connection 0 according to which modification of my invention may beused.

Referring now exclusively to the modification shown on the left-handside of the diagram, the wire 0 from the switch to the conductor-sectionconnects with the latter at the extreme end thereof. At the otherextreme end of the conductor T a shunt connection 0 is carried to theenergizing-coil B of the switch B. The other end of the coil B isconnected by wire G to the rail or return side of the circuit. The modeof operation of this arrangement is obvious. As long as the conductor Tremains intact throughoutits length it receives current from A throughF, through 0, through B through B, and through 0, and a car-having oneterminal engaging T and the other engaging It may receive the necessarypower. The current for the energizingcoil evidently takes the same pathand must in addition pass through the whole length of the conductor Tbefore reaching the energizing-coil. The moment therefore an opencircuit occurs at any point in the length of the conductor T current canno longer be received by the energizing-coil and the armature B mustfall upon the stop S. Thus before the conductor T falls sufficiently todo any damage it is no more than a dead wire. It is clear that this isan extremely simple arrangement for the purpose specified, and it isalso clear that the scope of my invention is notdependentupon anyspecial mechanical construction of the parts. It is also clear that I amnot limited in its use to electric railways. It is obvious also thatresistances may be inserted in line with the energizing-coil, if de*sired, without affecting the principle of my invention.

Referring now to the modification shown at the right hand of thedrawing, I here show an arrangement which is preferable when theconductor T is one of considerable length. In this case I connect theelectromagnetic switch B by connection C with a central part of theconductor-section T. I also form the coil B with a pair of cumulativewindings, one of which is connected by wire C with one end of theconductor-section, while the other is connected by wire 0 with the railor return side of the circuit. In this each winding magnetizes the core13 and tends to attract the armature B In this arrangement, however, Iso arrange the strength of the winding in comparison to the weight ofthe armature that if current is not passing through both windings thearmature B will fall. In this case it is clear that a break of theconductor-section T at any point in the length thereof must renderinoperative one or other of the windings, and therefore the samepractical results will be attained. The advantage of this arrangement isthat under the same relative conditions of load and conductor resistancetwice as long a conductor-section may be used and the expense ofsupplying the safety devices cut in half.

Having thus described my invention, what 1 claim, and desire to protectby Letters Patent, is

1. The combination with a feeder in connection with one side of the maincircuit, a suspended bared conductor, an electromagnetic switch normallyconnecting the same, said switch being normally maintained in a closedposition by current passing from the conductor through theenergizing-coil of the electromagnet, to the opposite side of thecircuit, said energizing-coil being in multiple relation with theregular working circuit.

2. The combination of a feeder in connection with one side of the maincircuit, a suspended bared conductor, an electromagnetic switch havingits terminals connected respectively to the main feeder and theconductor, and an energizing-coil for said switch comprising a singlewinding connected at one end to one end of the suspended conductor andat the other end to the opposite side of the circuit, armature of saidswitch being normally magnetized by current passing through the entirelength of said conductor.

3. The combination of a main feeder in connection with one side of thecircuit, a bared conductor, an electromagnetic switch connected to themain feeder and to a central portion of said conductor and anenergizing-ooil composed of two windings, one of which is connected toone end of the conductor and the other to the other end of theconductor.

4:. The combination of a main feeder in connection with one side of thecircuit, a bared conductor, an electromagnetic switch connected to themain feeder and to a central portion of said conductor and anenergizing-coil composed of two cumulative windings, one of which isconnected to one end of the conductor and the other to the other end ofthe conductor.

5. The combination of a feeder in connection with one side of the maincircuit, a suspended bared conductor, a return-conductor, anelectromagnetic switch having its terminals connected respectively tothe said feeder and to a central portion of the bared conductor, and anenergizing-coil for the switch having two cumulative windings each 0011-nected to the return-conductor at one end and connected to the oppositeends of the said bared conductor at the other end.

In testimony whereof I have affixed my signature in presence of twowitnesses.

JOSEPH N. THOMAS.

Witnesses:

RICHARD EYRE, H. W. SMITH.

